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a: \(=\dfrac{5}{4}\cdot\dfrac{2}{5}\cdot\dfrac{17}{21}\cdot\dfrac{7}{34}=\dfrac{1}{2}\cdot\dfrac{1}{2}\cdot\dfrac{1}{3}=\dfrac{1}{12}\)
b: =>0,5^x(0,5+1)=1,5
=>0,5^x=1
=>x=0
c: =>x*0,05-0,25*x=-1,2
=>-0,3*x=-1,2
=>x=4
d: =>x-1=1 hoặc x-1=-1
=>x=0 hoặc x=2
e: =5+4=9
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a)( \(\dfrac{-8}{40}\)+\(\dfrac{25}{40}\))+(\(\dfrac{-3}{8}\))
=\(\dfrac{17}{40}\)+(\(\dfrac{-3}{8}\))
=\(\dfrac{17}{40}\)+(\(\dfrac{-15}{40}\))
=\(\dfrac{2}{40}\)
=\(\dfrac{1}{20}\)
b)\(\dfrac{-5}{21}\)-(\(\dfrac{16}{21}\)-\(\dfrac{21}{21}\))
=\(\dfrac{-5}{21}\)-\(-5\)
=\(\dfrac{-25}{105}\)-\(\dfrac{-105}{105}\)
=\(\dfrac{16}{21}\)
bằng đây thôi nha mỏi tay quá
c: =3/7(-5/11+6/11)=3/7*1/11=3/77
d:=8/-3(4/3-7/3)=8/3
e: =3,4-5/8-0,4-3/8
=2-1
=1
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a, [ ( x + 12 ) - 7 ] : 13 = 2
(x+12) - 7 = 26
x+12= 33
x= 21
b, 240 - ( x + 8 ) : 2 = 120
(x+8):2 = 120
x+8 = 240
x= 232
c , 17 + ( x + 5 ) : 3 = 21
(x+5):3 = 4
x+5 = 12
x= 7
d, 10 = 2x - 38 - 18
<=> 2x - 38 - 18 = 10
2x - 56 =10
2x = 66
x=33
e, 3x - 19 = x + 11
3x - x = 11 +19
2x = 30
x=15
g, 7x - 2x = 325 : 13
5x = 25
x=5
h, 8,1 = 2x + x
8,1 = 3x
2,7 =x
i, 2x : 7 x 0,3 = 0,06
2x:7 = 0,2
2x = 1,4
x=0,7
k, .1,7 - x = 4x - 2,8
5x = 4,5
x=0,9
m, 1,2 - ( x - 7 ) : 0,2
(câu này kì qá, biểu thức ko có kq à?)
3x : 5 + x : 5 = 8
4x : 5 = 8
4x = 40
x=10
2x : 0,4 + x : 0,4 = 0,03
3x : 0,4 = 0,03
3x = 3/250
x= 1/250
2x + x + 4x = 0,49
7x = 0,49
x= 0,07
4x - x - 2x = 15
(4-1-2) x=15
x=15
3x + 5x - 6 = 10,5 - 0,3x
8,3x = 16,5
x= 165/83
2,5x + 7,5x - 15 = 5 x 10 : 2
10x = 25 + 15
10x = 40
x=4
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1: 0,35*12,4=0,35*2,4+0,35*10=3,5+0,84=4,34
2: =0,1-2,34=-2,24
3: =5-2,9=2,1
4: \(=2,5\left(10,124-0,124\right)=10\cdot2,5=25\)
5: =-3/7+1/13
=-39/91+7/91
=-32/91
6: =-1/3+1/3=0
\(0,4x-\frac{21}{5}=2\)
\(0,4x-4,2=2\)
\(0,4x=2+4,2\)
\(0,4x=6,2\)
\(x=6,2:0,4\)
\(x=15,5\)
~Học tốt~
\(0,4.x-\frac{21}{5}=2\)
\(\frac{2}{5}.x-\frac{21}{5}=2\)
\(\frac{2}{5}.x=2+\frac{21}{5}\)
\(\frac{2}{5}.x=\frac{12}{5}\)
\(x=\frac{12}{5}:\frac{2}{5}\)
\(x=6\)